The invention generally relates to automated sortation and other processing systems, and relates in certain embodiments to robotic systems for sorting objects (e.g., parcels, packages, articles etc.).
Current distribution center sorting systems, for example, generally assume an inflexible sequence of operations whereby a disorganized stream of input objects is first singulated by human workers into a single stream of isolated objects presented one at a time to a human worker with a scanner that identifies the object. The objects are then loaded onto a conveyor, and the conveyor then transports the objects to the desired destination, which may be a bin, a chute, a bag or a destination conveyor.
In typical parcel sortation systems, human workers typically retrieve parcels in an arrival order, and sort each parcel or object into a collection bin based on a given heuristic. For instance, all objects of like type might go to a collection bin, or all objects in a single customer order, or all objects destined for the same shipping destination, etc. The human workers are required to receive objects and to move each to their assigned collection bin. If the number of different types of input (received) objects is large, a large number of collection bins is required.
Such a system has inherent inefficiencies as well as inflexibilities since the desired goal is to match incoming objects to assigned collection bins. Such systems may require a large number of collection bins (and therefore a large amount of physical space, large capital costs, and large operating costs) in part, because sorting all objects in unison is not always most efficient.
Current state of the art sortation systems rely on human labor. Most solutions rely on a worker that is performing sortation, by scanning an object from an induction area (chute, table, etc.) and placing the object in a staging location, or collection bin. When a bin is full or the controlling software system decides that it needs to be emptied, another worker empties the bin into a bag, box, or other container, and sends that container on to the next processing step. Such a system has limits on throughput (i.e., how fast can human workers sort to or empty bins in this fashion) and on number of diverts (i.e., for a given bin size, only so many bins may be arranged to be within efficient reach of human workers).
Partially automated means of solving this problem are lacking in key areas. Such approaches typically involve tilt-tray or bomb-bay style recirculating conveyors. These conveyors have discrete trays that can be loaded with an object. The trays and objects then pass through scan tunnels that scan the object and associate it with the tray in which it is riding; when the tray passes the correct bin, a trigger mechanism causes the tray to dump the object into the bin. A drawback of such systems is that every divert requires an actuator, which increases the mechanical complexity and the cost per divert can be very high. For applications requiring hundreds of diverts, the large cost of such a system does not achieve a good return on investment.
An alternative is to use human labor to increase the number of diverts, or collection bins, available in the system. This decreases system installation costs, but increases the operating costs. Manual sortation cells are staffed by a team of workers, which avoids the large cost per divert. Multiple cells can then work in parallel, effectively multiplying throughput linearly while keeping the number of expensive automated diverts at a minimum (equal to the number of parallel sortation cells, not the total number of system bins needed). This approach involves objects for sortation being supplied to each cell, which can be done manually but is easily done via means of a conveyor with sweep arms or other dumb diverts to each work cell. Such diverts do not identify an object and cannot divert it to a particular spot; rather they work with beam breaks or other simple sensors to seek to make sure that indiscriminate bunches of objects get diverted to each cell. The lower cost of the unsophisticated diverts coupled with the low number of diverts keeps the overall system divert cost low.
Unfortunately however, these systems don't address the limitations to total number of system bins. The system is simply diverting an equal share of the total objects to each parallel manual cell. Each parallel sortation cell must therefore have all the same collection bins designations; otherwise an object might be delivered to a cell that does not have a bin to which that object is mapped. There remains a need for a more efficient and more cost effective object sortation system that sorts objects into appropriate collection bins, yet is more efficient in operation.